TWO weeks ago we covered a fabulous topic about the world in four billion years, this led us to go further to see what happened when the world was still going through different geological and metrological changes.
According to paleontologists say the Earth was formed about 4.5 billion years ago when the universe expanded due to what scientists say very high density and high temperature which resulted from the initial expansion that took place about 13.8 billion years ago when the universe came into being.
History of the world tells us that a primitive process of photosynthesis came into existence after the evolution of oxygen into the Earth about 3.5 billion years ago, scientists believe that this important chemical element appeared earlier about 3.7 billion years ago when the atmosphere was composed mainly by volcanic and greenhouse gases.
Meanwhile paleontologists say that happened in the ancient time of Ur a supercontinent that formed about 3 billion years ago and perhaps the oldest continent on Earth, the early period of Ur’s existence, it was probably the only continent on Earth and all other land was in the form of small granite islands and small landmasses that were not large enough to be continents.
About 2000 years ago in the Biblical world Ur is said to be the birth place of Abraham the grandfather of Abrahamic faiths, on the other side scientists believe that during the existence of Ur supercontinent the evolution of plants which used ancient photosynthesis become a catalyst for existence of life on planet because the process began to enrich the atmosphere with good amount of oxygen about 2.4 billion years ago when the world was still dominated with microscopic organisms.
Different researches indicate that about 1.5 billion years ago the Earth passed through a long ice age which wiped out most of ancient plants that existed in the prehistoric world but scientists say different kind of earliest organisms continued to thrive.
Some scientific researches indicate that the first animal to evolve with what may be called an ancient eye appeared about 600 million years ago, but through genetic features researchers have discovered that the real eye among vertebrates evolved about 540 million years ago.
It is estimated that about 580 million years ago the availability of enough oxygen contributed again into the evolution of complex multicellular organisms a group which was mainly made by bacteria, this shows that right from the beginning of the time photosynthesis played a very important role into the existence of life in different ecosystem of the world.
Furthermore, paleontologists say between 555 and 539 million years ago ancestors of all arthropods started to evolve on the Earth’s surface, these were ancient creatures who about 530 million years ago started to undergo different changes which enabled them to thrive under sea bed until 525 million years ago when some of them such as the giant dragonfly which used its 55 to 70 centimeters wingspan to migrate and dominate the ancient world.
Meanwhile through the use of fossils records scientists estimate the first animal carrying an eye evolved more than 540 million years ago when the world was dominated by creatures with exoskeletons.
Different researches indicate that the first eyed animals had light sensitive mechanism which depended on photoreceptors cell which originated from their ancestors which had very weak brain that was being controlled other parts of their bodies, fossils records indicates that evolution of an eyes took good stage about 525 million years ago when the first ancestors of vertebrate animals evolved into the earth.
Scientists say during those days an ancient super predators evolved with powerful vision which helped them to chase and capture their prey in a difficult about 485.4 million years ago when the planet was still recovering from an earlier weather which was dominated by falling of snow from the sky.
Different fossils records show about 450 million years ago the first land plant evolved and thrived following advancement of the ancient photosynthesis process.
To survive in an ancient world which was experiencing low oxygen with big amount of carbon dioxide from volcanic activities, about 360 million years ago plants developed a well mechanism which used stomata and adapted xylem and phloem vascular tissues which enabled them to spread into different ecosystems including arid and semi-arid lands where the savannah is available today.
It was during this period about 360 million years ago when ancestors of modern green plants got well defined leaves, that was an important stage of evolution for plants because the presence of vascular conducting system helped them to use their environment effectively by obtaining carbon dioxide from the atmosphere and roots which draw water from the ground.
History of the world show the Earth passed different changes but powerful volcanic activities led to the formation of Pangaea a new supercontinent which emerged about 300 million years ago after smaller continents were assembled together, different researches indicate that much of Pangaea was in the southern hemisphere and surrounded by a super ocean, Panthalassa and this makes Pangaea to be the last supercontinent to have existed.
The world’s history shows the emerging of Pangaea enabled evolution of mammals on the Earth about 320 million years ago but they were less known to other creatures until 250 million years ago when a mass extinction event killed 70 per cent of vertebrates.
From an egg laying mammal, evolution of this group passed different stages but from those days to date their offspring start life without teeth to cut or grind food stuffs. Unlike fishes, reptiles and other creatures, from those prehistoric days to date mammals start their life without a well-developed digestive system.
Historians and geologists say its very interesting that unlike Olduvai gorge which is well known all over the world, Tendaguru a small village in Lindi rural district is one of the first places in the world were dinosaurs used to dwell. Paleontologists say dinosaurs evolved on Earth more than 243 million years ago and managed to conquer rainforest and savannah when a mass extinction killed other creatures about 201 million years ago.
About 231 million years ago, it was on this super continent where Rukwatitan Bisepultus and other dinosaurs dwelled in the land where Tanzania and other east African countries are found today. Scientific researches indicate the southern part of Tanzania attracted dinosaurs from different parts of the world including Asilisaurus which evolved more than 244 million years ago.
Historians and scientists named this specie by using a Swahili name which indicates the original of dinosaurs in the world to be Tendaguru in southern Tanzania. Paleontologists say Asilisaurus were from 0.5 to 1metres from their hips with a body which measured from 1 to 3 metres and weighed between 10 to 30 kilogrammes.
This shows that Asilisaurus were very small and could not block the evolution of specie called Nyasasaurus which took place in southern Tanzania more than 243 million years ago. Historians believe that Asilisaurus evolved in Tendaguru more than 12 million years before other species of dinosaurs and managed to overcome different challenges as they developed a habit of eating every plants and animal at their disposal.
Time after time, population of Asilisaurus increased and they moved southward were confronted with Nundasuchus, a group of dinosaurs which occupied the plains on the side of lake Nyasa from about 241 million years ago. Scientists say Nundasuchus were bigger than other dinosaurs of their time because an individual which appeared in Manda about 240 million years ago on a body which stretched from two to seven metres.
As their name goes, Nundasuchus were predators which preyed upon other animals including weaker dinosaurs. Through different fossils its believed that Nundasuchus were formidable fighters which were armed with sharp teeth and their bodies had protective hard shell which enabled them to came out of an encounter without injuries.
All these events took place in the prehistoric supercontinent of Pangaea which Paleontologists say through three stages it disintegrated about 175 million years ago. Paleontologists say that was very important in the Earth history because different climatic changes took place and enabled the evolution of flowerlike plant about 150 million years.
Fossils records show that ancestors of flies and beetles were the first agents of the ancient pollination process but about 145 million years ago prehistoric generation of bees contributed massively in this process as they collected nectars from one plant to another while playing a key role in distribution of pollens and enabled expansion of flowering plants into different ecosystems.
It was during this period when climate restricted ice sheets on high lands and mountain and opened the rest of the world for flowering plants to thrive in the world which supported evolution of wasp and termites into the growing forests and savannah of the ancient world.
Scientists say the Savannah is the latest ecosystem to emerge in Africa and other parts of the World as a result of a huge climate changes accompanied with a rise of temperature and decrease of rainfalls.